Heart valve implants with side slits

ABSTRACT

A cardiac implant system including a cardiac implant such as an annuloplasty ring, a prosthetic heart valve, or a valved conduit pre-assembled at the time of manufacture with devices for securing the implant to a heart valve annulus using knotless suture fasteners. The knotless suture fasteners may be embedded within a pliant sealing edge of the cardiac implant, or they may be positioned adjacent to the sealing edge. The knotless suture fasteners are spring-biased so as to grip onto annulus anchoring sutures pass to therethrough upon removal of a restraining device, such as a hypotube inserted within the suture fasteners. Guide tubes are assembled in line with the suture fasteners to permit introduction of suture snares that pass through the suture fasteners and through the sealing edge to facilitate capture of the pre-installed annulus anchoring sutures.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/625,801, filed Jun. 16, 2017, now U.S. Pat. No. 10,314,706, which isa continuation of U.S. patent application Ser. No. 15/295,912, filedOct. 17, 2016, now U.S. Pat. No. 9,968,451, which is a continuation ofU.S. patent application Ser. No. 14/302,733, filed Jun. 12, 2014, nowU.S. Pat. No. 9,468,527, which claims the benefit of U.S. PatentApplication No. 61/834,356, filed Jun. 12, 2013, the entire disclosuresall of which are incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to a prosthetic cardiac implanthaving a knotless suture fastening system assembled therewith forsecuring the valve to a native annulus without requiring suture knots.

BACKGROUND OF THE INVENTION

Heart valve disease is a widespread condition in which one or more ofthe valves of the heart fails to function properly. Diseased heartvalves may be categorized as either stenotic, wherein the valve does notopen sufficiently to allow adequate forward flow of blood through thevalve, and/or incompetent, wherein the valve does not close completely,causing excessive backward flow of blood or regurgitation through thevalve when the leaflets are supposed to coapt together. Valve diseasecan be severely debilitating and even fatal if left untreated.

Various surgical techniques may be used to repair a diseased or damagedvalve, including securing a cardiac implant to the diseased annulus.Cardiac implants include prosthetic heart valves, valved conduits andannuloplasty rings. In a valve replacement operation, the damagedleaflets are excised and the annulus sculpted to receive a replacementvalve. Worldwide, approximately 300,000 heart valve replacementsurgeries are performed annually, and about one-half of these patientsreceived mechanical heart valves, which are composed of rigid, syntheticmaterials. The remaining patients received bioprosthetic heart valvereplacements, which utilize biologically derived tissues for flexiblefluid occluding leaflets. Prosthetic heart valves may be implantedindependently in one of the orifices or annuluses of the heart, or maybe coupled to a flow conduit which extends in line with the valve apredetermined distance. For example, valved conduits can be designed forreconstruction of portions of the flow passage above and below theaortic valve, such as the ascending aorta, in addition to replacing thefunction of the valve itself. Another less drastic method for treatingdefective valves is through repair or reconstruction, which is typicallyused on minimally calcified valves. One repair technique that has beenshown to be effective in treating incompetence is annuloplasty, in whichthe deformed valve annulus is reshaped by attaching a prostheticannuloplasty repair segment or ring to the valve annulus.

In a typical cardiac implant procedure, the aorta is incised and, in avalve replacement operation, the defective valve is removed leaving thedesired placement site that may include a fibrous tissue layer orannular tissue. Known cardiac implant techniques include individuallypassing sutures through the fibrous tissue or desired placement sitewithin the valve annulus to form an array of sutures. Free ends of thesutures are extended out of the thoracic cavity and are spaced apart,sometimes being distributed around a suture organizer. The free ends ofthe sutures are then individually threaded through a suture-permeablesealing edge of the annuloplasty ring or prosthetic heart valve. Onceall sutures have been run through the sealing edge (typically 12 to 18sutures), all the sutures are pulled up taught and the prosthesis isslid or “parachuted” down until it sits against the target annulus. Thecardiac implant is then secured in place by traditional knot tying ofthe anchoring sutures on the proximal side of the sealing edge. Thisprocedure is time consuming as doctors often use three to ten knots persuture.

During open-heart procedures, the patient is on heart-lung bypass whichreduces the patient's oxygen level and creates non-physiologic bloodflow dynamics. The longer a patient is on heart-lung bypass, the greaterthe risk for complications including permanent health damage. Existingtechniques for suturing cardiac implants extend the duration of bypassand increase the health risks due to heart-lung bypass. Furthermore, thesecuring force created by suturing varies significantly because thepre-tensioning of the suture just prior to knot tying is difficult toconsistently maintain, even for the same medical professional.

There exists a need for devices and methods that reduce the timerequired to secure a heart valve repair prosthesis in place. Currently aclinician must tie a multitude of knots in sutures which can take agreat deal of time and lengthens the time a patient is oncardio-pulmonary bypass and under anesthesia. Additionally, there existsa need to make it easier to secure a heart valve repair prosthesis(e.g., an annuloplasty ring) in place. Currently, a clinician must workin the limited space near the heart to tie knots in sutures. This is acumbersome process that benefits from a clinician of great dexterity andpatience.

SUMMARY OF THE INVENTION

The present invention provides improved knotless suture fasteners andsystems for securing a cardiac implant such as an annuloplasty ring or aprosthetic heart valve or valved conduit to a heart valve annulus. Theapparatus and methods are particularly well suited for traditionalsurgery or minimally invasive surgery. The devices disclosed hereineliminate the need for surgical knots thus reducing surgical time andexposure. Further, the devices improve the ease of implantation becausethe clinician need not tie knots in the limited space in and around theheart. The knotless suture fasteners are simple to deploy and theiractuation does not affect suture tension. The implant systems arepre-assembled at the time of manufacture with the cardiac implants. Theknotless suture fasteners may be embedded within a pliant sealing edgeof the cardiac implant, or they may be positioned on one face of thesealing edge. One embodiment of the knotless suture fasteners includessmall tubes having tabs that are spring-biased inward so as to grip ontoannulus anchoring sutures passing therethrough upon removal of arestraining device, such as a hypotube inserted within the tubularsuture fasteners. Another embodiment includes a bifurcated lockingclamp, a biasing member positioned on the outside of the locking clamp,and a retention member positioned between the clamp halves. Regardlessof what type of fastener is used, it is positioned adjacent a slit inthe sealing edge such that the physician need not pass needles throughthe sealing edge to engage the implant sutures with the fastener.

A preferred cardiac implant system comprises a cardiac implant having aninner frame arranged around a flow axis through the implant along whichblood will flow when implanted from an inflow side to an outflow side ofthe implant. A pliant sealing edge extends outward from the inner frameand has inflow and outflow faces. The sealing edge also has formedtherein a plurality of generally axial slits that open radially outward.A plurality of knotless suture fasteners are distributed around thesealing edge and attached thereto. Each fastener has an axial slot sizedto receive a suture facing radially outward, and each fastener islocated adjacent one of the axial slits in the sealing edge such that asuture may be passed through the slit and into the axial slot of thefastener. The fasteners have an open state which permits a suture toslide axially therethrough and a closed state which prevents axialmovement of the suture in at least one direction. The fasteners may beat least partially embedded into and secured in the sealing edge, or maybe positioned on one of the inflow or outflow faces of the sealing edgeand attached thereto.

In the aforementioned cardiac implant system, each suture fastener mayhave an outer wall defining a lumen extending from a proximal end to adistal end and a collapsible wall structure, wherein the collapsiblewall structure in the open state does not restrict relative movementbetween the fastener and a suture therein and the collapsible wallstructure in the closed state restricts movement of a suture through thefastener in at least one direction. In this configuration, each fastenerfurther includes a retention member coupled thereto in the open state,the retention member having a hypotube which fits closely within thelumen of the fastener and maintains the collapsible wall structure inits open state, and upon removal of the retention member and hypotube,the fastener converts to the closed state and the collapsible wallstructure collapses inward to clamp onto a suture. In an embodimentwhere the suture fastener is embedded in the sealing edge, a flangeextends outward from the outer wall at a proximal end thereofsufficiently large to prevent the fastener from pulling through thepliant sealing ring.

In an alternative embodiment, each suture fastener comprises abifurcated locking clamp including a pair of substantially similar clamphalves each having an exterior surface and an inner surface facing theinner surface of the other clamp half to form a variable sized slottherebetween. The clamp halves are connected for movement toward or awayfrom one another while being fixed axially with respect to one another,wherein the suture(s) extend through the slot between the inner surfacesof the clamp halves. A biasing member positioned on the outside of thelocking clamp has a relaxed size that, in the absence of an object inthe slot, urges the inner surfaces of the clamp halves together.Finally, a retention member is positioned between the clamp halvesagainst the force of the biasing member and has a thickness thatmaintains the slot width large enough to permit passage of a suturetherethrough, wherein removal of the retention member permits thebiasing member to urge the inner surfaces of the clamp halves togetherand clamp the suture therebetween. The clamp halves may be molded from asingle piece of material with a living hinge on the firstcircumferential side. The clamp halves are desirably hinged together ona first circumferential side such that the variable sized slot defines avariable sized opening on the side opposite the first circumferentialside, and wherein the biasing member comprises a plurality of C-clipsarranged around the locking clamp with their free ends located on eitherside of the variable sized slot opposite the first circumferential side.

For the fasteners disclosed herein, a retention member coupled to thefastener maintains the fastener in the open state and when removedconverts the fastener to the closed state, and wherein a plurality ofthe retention members may be tethered together.

The cardiac implant may be a prosthetic heart valve comprising occludingmembers that provide one-way flow through the valve movably mounted tomove within the inner frame, wherein the pliant sealing edge comprises asealing ring secured to the outside of the inner frame. There may beonly three of the suture fasteners located around the sealing ring.Further, the inner frame may partly extend in an outflow direction toform three cantilevered commissures evenly distributed around the flowaxis that support flexible leaflets, and the prosthetic heart valvefurther includes a plastically-expandable anchoring skirt coupled to thesealing ring and extending from an inflow end thereof, the three suturefasteners being located around the sealing ring intermediate thecommissures. Alternatively, the cardiac implant is an annuloplasty ring,wherein the inner frame comprises a structural core and the pliantsealing edge surrounds the core and has a fabric cover. In yet anotherembodiment, the cardiac implant is a valved conduit, comprising a valvehaving a conduit coupled thereto and having a sealing edge surroundingthe inflow end.

An exemplary method of securing a cardiac implant to a heart valveannulus, comprises:

providing a pre-assembled cardiac implant system including an implanthaving an inner frame surrounding a flow axis through the implant alongwhich blood will flow when implanted from an inflow side to an outflowside of the implant, the implant including a pliant sealing edgeextending outward from the inner frame with a plurality of generallyaxial slits that open radially outward, the system further including aplurality of knotless suture fasteners attached to and distributedaround the sealing edge at the locations of the axial slits;

pre-installing at least one anchoring suture at the heart valve annulus,each anchoring suture being passed at least once through the heart valveannulus with free end(s) extending away from the annulus;

passing each of the free end(s) of the anchoring sutures radially inwardthrough one of the axial slits in the sealing edge and into thecorresponding suture fastener;

advancing the cardiac implant until the pliant sealing edge seatsagainst the annulus;

deploying the suture fasteners to clamp onto the free end(s) of theanchoring sutures; and

severing each of the free end(s) of the anchoring sutures close to theproximal end of the respective suture fastener.

The cardiac implant may be a prosthetic heart valve, and the inner framepartly extends in an outflow direction to form three cantileveredcommissures evenly distributed around the flow axis. The valve also hasthree flexible leaflets each supported by two of the commissures with afree edge therebetween that coapts with the other flexible leaflet freeedges along the flow axis to provide one-way flow through the valve. Thepliant sealing edge therefore comprises a sealing ring secured to theoutside of the inner frame. The prosthetic heart valve may furtherinclude an anchoring skirt coupled to the sealing ring and extendingfrom an inflow end thereof, and the method includes expanding theanchoring skirt below the heart valve annulus, wherein the method ofsecuring the prosthetic heart valve to the annulus consisting only ofexpanding the anchoring skirt and attaching the three sutures and suturefasteners.

In one aspect of the method described above, each of the suturefasteners is embedded within the sealing edge of the cardiac implant.The implant may alternatively be an annuloplasty ring, wherein the innerframe may comprise a metallic core and the pliant sealing edge comprisesa silicone sleeve surrounding the core and a fabric cover over thesleeve. Each fastener preferably includes a retention member such as aretention pin that when coupled to the fastener maintains the fastenerin the open state and when removed converts the fastener to the closedstate, wherein a plurality of the retention pins are tethered togetherand the method includes sequentially removing a plurality of retentionpins that are tethered together from adjacent fasteners.

A further understanding of the nature and advantages of the presentinvention are set forth in the following description and claims,particularly when considered in conjunction with the accompanyingdrawings in which like parts bear like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained and other advantages and featureswill appear with reference to the accompanying schematic drawingswherein:

FIGS. 1A-1C are drawings of several steps in a procedure for implantinga heart valve at an aortic annulus using the techniques and an exemplary“side entry” knotless fastener of the present application;

FIG. 2 is a perspective view of a flexible leaflet prosthetic heartvalve after deployment of a plurality of exemplary tubular side entryfasteners distributed around a peripheral sealing edge;

FIG. 2A is an enlarged view of one tubular knotless suture fastener inthe prosthetic heart valve of FIG. 2, while FIG. 2B is a cross-sectiontherethrough showing the fastener embedded in a pliant sealing ring;

FIG. 3 is a plan view of an exemplary annuloplasty ring having embeddedtubular side entry fasteners;

FIG. 3A is an enlarged view of a tubular side entry fastener in theannuloplasty ring of FIG. 3, while FIG. 3B is a cross-sectiontherethrough showing the fastener embedded in a sealing edge;

FIGS. 4A-4C are enlarged and sectional views showing a tubular sideentry fastener and retention pin isolated from the cardiac implants forclarity, while FIG. 4D shows an alternative configuration of the tubularfastener;

FIGS. 5A and 5B show the tubular side entry fastener embedded in asealing ring of a prosthetic heart valve before and after deployment;

FIG. 6 is a perspective view of several internal components a flexibleleaflet prosthetic heart valve and a plurality of the tubular side entryfasteners;

FIG. 7A is a perspective view of a disk-shaped sealing ring inserthaving holes around its periphery for receiving the tubular side entryfasteners and retention pins;

FIG. 7B is a perspective view of the sealing ring insert of FIG. 7Aabove a sealing ring sponge and having the tubular fasteners extendingwithin outer recesses formed within the sponge;

FIG. 7C is a perspective view of the components in FIG. 7B with atubular fabric piece disposed within the annular sponge prior towrapping and sewing around the subassembly;

FIG. 7D is a perspective view of a stent subassembly of the componentsshown exploded in FIG. 6 covered and joined together with fabric;

FIG. 8 is a perspective view of a leaflet subassembly of afabric-covered undulating wireform having flexible leaflets attachedthereto and extending inward into a flow orifice defined thereby, andFIG. 8A is a sectional view through one edge of the leaflet subassembly;

FIG. 9 is a perspective view of a completed prosthetic heart valvehaving the tubular side entry fasteners and corresponding retention pinsaround its sealing ring periphery, and illustrating small vertical slitsin the outer edge of the sealing ring at the circumferential location ofthe fasteners;

FIG. 9A is a sectional view through the prosthetic heart valve of FIG. 9showing the position of one of the tubular side entry fasteners withinthe sealing ring;

FIG. 9B is an enlarged view of one of the side entry fasteners lookingdirectly radially inward through the vertical slit in the sealing ringof FIG. 9;

FIGS. 10A and 10B are perspective views of an alternative split “sideentry” suture fastener having a bifurcated locking clamp with an axialhinge biased closed by exterior C-springs;

FIG. 11 shows just the bifurcated locking clamp, while FIG. 12 shows aninner wall structure of one half of the clamp;

FIG. 13A shows one of the C-springs, and FIG. 13B shows an alternativeC-clip in the form of a split tube;

FIGS. 14A-14D are perspective views of a sequence of operation of theside entry suture fastener;

FIG. 15 is a perspective sectional view of the side entry suturefastener clamped onto a suture that is pre-attached at one end to thedevice, and showing how the suture(s) can be tensioned further;

FIG. 16A is a perspective view of a flexible leaflet prosthetic heartvalve having a number of the split side entry fasteners distributedaround its sealing ring which has vertical slits at the circumferentiallocation of each one of the fasteners;

FIG. 16B is a sectional view through the prosthetic heart valve of FIG.16A showing the position of one of the tubular side entry fasteners ontop of the sealing ring;

FIG. 17A is an enlarged view of one of the side entry fasteners lookingdirectly radially inward through the vertical slit in the sealing ringof FIG. 16A and prior to deployment, while FIG. 17B shows the fastenerafter deployment by removal of a retention pin;

FIG. 18A is a perspective view of a hybrid prosthetic heart valve with acloth-covered anchoring skirt expanded against a subvalvular wall belowan aortic annulus and illustrating three of the split side entryfasteners positioned above a sealing ring thereof, and FIG. 18B is a topplan view of the prosthetic heart valve showing distribution of thesplit fasteners at the valve cusps;

FIG. 19 is a perspective view of an alternative split side entryfastener having an enlarged upper flange with sewing holes therein;

FIGS. 20A and 20B are sectional views through a prosthetic heart valvehaving one of the side entry fasteners of FIG. 19 embedded in a sealingring therein before and after deployment;

FIGS. 21A-21D illustrate several components and steps in assembling aprosthetic heart valve having the embedded side entry fasteners of FIGS.19-20;

FIG. 22 is a perspective exploded view of an exemplary multiple suturefastener loading fixture of the present application;

FIG. 23 is a perspective assembled view of the loading fixture of FIG.22, while FIG. 23A is a sectional view through one of a plurality ofload stations therein;

FIG. 24 is a perspective view of the loading fixture;

FIGS. 25 and 25A are sectional views through the load station in whichthe retention pin is entering showing a retention pin entering thelead-in cavity; and

FIGS. 26A-26C are sectional views through one of the load stationsshowing steps in transferring an exemplary suture fastener from the loadstation to the retention pin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides improved systems for securing a cardiacimplant to a heart valve annulus using knotless fasteners. The systemsdescribed herein each includes a prosthetic implant pre-assembled withthe knotless fasteners. The term “pre-assembled” means that the cardiacimplants are assembled by the manufacture and packaged along with thesuture fasteners which are positioned for deployment. In one version,the suture fasteners are embedded within a sealing edge on the cardiacimplant, while in another version the suture fasteners are positioned incontact with a proximal face of the sealing edge. Proximal and distalrefer to the opposite directions toward and away, respectively, from asurgeon performing the implant. In either case, because the suturefasteners are pre-assembled with the cardiac implant and positioned fordeployment, their installation is greatly facilitated.

The knotless suture fasteners described herein include self-actuating orspring-loaded devices that clamp onto sutures. Passing one or moresutures through the device and then converting it from an open to aclosed state causes features to collapse inward and clamp onto thesuture(s). The conversion desirably occurs upon removal of an impedimentto inward motion of clamping elements, though other spring-loadedconfigurations are possible. Such self-actuating suture fasteners arepreferred over plastically-deformable fasteners which must be crimpedover the sutures using forceps or other such compression tools. On theother hand, for added security a portion of the suture fastenersdisclosed herein may be deformable so that a user may crimp it onto thesutures—a hybrid fastener. For the purpose of defining terms, the term“self-actuating” suture fastener refers to a spring-biased type ofdevice which does not require crimping, but which, on the other hand,does not exclude a crimpable portion. A “self-actuating” suture fasteneris not entirely autonomous, in that there is a trigger prior to thedeployment, such as removal of an element or change in temperature, butthe term excludes devices that require mechanical crimping using anexternal tool.

Alternative self-actuating fasteners may be made of atemperature-activated memory material that biases the fastener to itsclosed configuration when exposed to a selected temperature range,though the control and timing of such devices add complexity. With thetemperature-activated memory material in its austenite state, thefastener tabs extend into the inner lumen to their greatest extent, sothat the fastener is in a “closed” configuration wherein the tabs blockmovement of any lengths of suture passing through the inner lumen. Theaustenite state can be set to occur when the suture fastener isgenerally unstressed and at human body temperature, so that whendeployed in the patient's body it will be remain biased toward itsclosed configuration.

It should also be understood that a suture fastener that is not at allspring-loaded, but instead is entirely plastically deformable may beused. For example, a rivet-style suture fastener may be positionedadjacent to or embedded within a cardiac implant sealing edge, as withthe exemplary self-actuating suture fastener. Although not shown, toolsfor crimping or actuating such alternative suture fasteners may beincluded in the implant system. In short, though there are distinctadvantages to a self-actuating or spring-loaded fastener, certainaspects of the present application may be exploited while using afastener that is crimped onto the anchoring sutures, and the disclosureshould not be considered limited to one type of fastener or anotherunless explicit in any one claim.

The term cardiac implant as used herein primarily refers to prostheticheart valves, valved conduits and annuloplasty rings or segments.However, the suture fastening systems described herein can be used toattach other prostheses such as stents, grafts, stent-grafts, fluiddelivery reservoirs, electro-stimulators, or the like. Furthermore, thecardiac implants are desirably secured at a target heart valve annulus,but the suture fastening systems may also be used to attach implants toother anatomical structures such as vessels, organs (e.g., intestine,heart, skin, liver, kidney) or other locations where sutures aretypically used to attach the implant.

FIGS. 1A-1C illustrate several steps in a surgical procedure forimplanting a prosthetic heart valve 20 at an aortic annulus AA, which isexposed by forming an incision in the ascending aorta or aortic arch.The heart valve 20 is representative of numerous types of heart valves,including those with flexible leaflets as shown, and also mechanicalvalves with rigid metallic leaflets. Further, the flexible leaflet heartvalve 20 is shown with a plurality of “side-entry” suture fasteners 22of the present application deployed from an outflow side of the valve,which typically indicates that the valve is for implant at the aorticannulus where the outflow is also the proximal side relative toconventional heart valve delivery. However, it should be understood thatthe suture fasteners 22 could be reversed within the heart valve 20 sothat they are deployed from the inflow side, such as in a mitral valvereplacement procedure. Therefore, the present implant system is suitablefor aortic valves, mitral valves and even pulmonic valves which are lesscommon.

The implant procedure illustrated is typical of surgical heart valvereplacement procedures, where the surgeon initially loops a plurality ofindividual sutures 24 through the aortic annulus AA so as to form anarray of pairs of sutures extending upward out of the operating site. Ina conventional surgical procedure, each separate pair of sutures 24 isthen passed through a pliant sewing ring of the heart valve. Bypositioning pairs of sutures 24 around the sewing ring atcircumferential locations corresponding to where they pass through theaortic annulus AA, the surgeon can then “parachute” the heart valve downthe array of sutures until the sewing ring seats against the aorticannulus AA. Subsequently, the pairs of sutures are tied off on theproximal side of the sewing ring to secure the valve to the annulus. Thesewing ring is pliant and conforms to the often uneven annulus, therebygreatly reducing paravalvular leakage. Sewing rings are typically formedof rolled fabric or silicone rubber sponges surrounded by fabric.

In contrast, the present application contemplates a number ofconfigurations of exemplary “side entry” knotless fasteners which botheliminate the necessity to pass a needle through a sewing ring and alsoeliminate the process of tying the sutures off with knots. This bothreduces the possibility of damaging the heart valve with a sutureneedle, and greatly reduces the time necessary to secure the valve tothe annulus.

FIG. 1A shows the heart valve 20 secured on a holder 26 that in turn iscoupled to the distal end of a delivery handle 28. A plurality of pairsof sutures 24 have already been inserted into knotless fasteners 22distributed around a sealing ring 30 of the valve, while one pair 24 ais shown just prior to engagement with a knotless fastener within thesealing ring. As seen, the suture pair 24 a is displaced radially towarda slit 32 in the outer edge of the sealing ring 30, which leads to aknotless fastener within the sealing ring, as will be described below.Although the heart valve 20 is shown just above the aortic annulus AA,this procedure may be done outside of the patient's body entirely. Itshould also be noted pairs of free ends of a looped suture are typicallyused when knots are tied, but since the fasteners 22 are “knotless,” asingle stranded suture may be passed through the aortic annulus AA witha pledget at the end anchored under the annulus. In either case, asuture is anchored to the annulus by either looping it or anchoring witha pledget with free end(s) extending upward out of the implant site forcoupling with the fasteners 22. From here on the term “a suture” refersto one or a pair of sutures.

Each fastener 22 has an open state which permits a suture 24 to slideaxially therethrough and a closed or deployed state which prevents axialmovement of the suture 24 in at least one direction. In a preferredembodiment, each of the knotless fasteners 22 may be deployed so as toretain the sutures 24 therein, while still permitting the surgeon toslide the heart valve 20 down the array of sutures. The process ofengaging each suture 24 with one of the knotless fasteners 22 continuesuntil all of the suture pairs are positioned around the heart valvesealing ring 30, after which time the valve is parachuted down the arrayof sutures until the sealing ring seats against the aortic annulus AA.The sealing ring 30 may be configured like the sewing rings ofconventional valves, such as with rolled fabric or fabric-coveredsilicone, but no sutures are passed through it and thus it is not calleda sewing ring. The sealing ring 30 provides a sealing edge at itsoutmost extent.

FIG. 1B shows the heart valve 20 seated at the aortic annulus AA andafter disconnection of the valve holder 26. In the illustratedembodiment, the holder 26 has 3 legs 27 that connect to valve cusps viasutures which can be severed to disengage the holder from the valve 20.The holder 26 and delivery handle 28 are typically removed from theimplantation site prior to severing the free ends of sutures 24, andotherwise checking for proper implantation. Finally, FIG. 1C shows theheart valve 20 after implantation with all of the sutures cut at thelevel of the sealing ring 30. The implantation site can then be closedup.

FIG. 2 is a perspective view of the prosthetic heart valve 20 afterdeployment of a plurality of exemplary tubular side entry fasteners 22distributed around the peripheral sealing ring 30, while FIG. 2A is anenlarged view of the fastener and FIG. 2B is a cross-section showing thefastener embedded in the sealing ring. The flexible leaflet heart valve20 preferably includes an internal frame or stent (FIG. 2B) which has acloth cover and defines three upstanding commissure posts 42 thatsupport three flexible leaflets 44 therebetween. The sealing ring 30attaches around the periphery of the internal frame at the inflow end ofthe valve, with the commissure posts 42 projecting in the outflowdirection. The leaflets 44 can be formed from separate flaps ofxenograft tissue, such as bovine pericardium, or all three leaflets canbe derived from a single xenograft valve, such as a porcine valve. Theleaflets 44 are secured and supported by the commissure posts 42, aswell as along arcuate cusps 46 in between the commissure posts.

There are desirably between 12-20 knotless suture fasteners 22distributed around the sealing ring 30. The number of suture fasteners22 partly depends on the size of the valve 20, with more fasteners beingused on larger valves. Furthermore, suture fasteners 22 may be placed atstrategic locations, such as adjacent to the commissure posts 42.Preferably, there is one suture fastener 22 aligned with each of thecommissure posts 42, and a number of suture fasteners evenly distributedbetween the commissure posts along the cusps 46. For instance, threesuture fasteners 22 may be distributed between the commissure posts 42such that one of them is centered in each of the cusps 46, for a totalof twelve suture fasteners.

FIG. 2A shows one of the tubular suture fasteners 22 embedded in thesealing ring 30. An upper edge of the fastener 22 projects above thesealing ring 30, while the majority of the body of the fastener iswithin the sealing ring. The axis of the tubular fastener 22 generallycorresponds to the central axis of the heart valve, which is synonymouswith vertical. The fastener 22 includes a vertical opening 48 in oneside thereof which is oriented radially outward toward and in line withthe vertical slit 32 formed in the sealing ring 30. The combination ofthe aligned slit 32 and opening 48 provides the entryway for the sutures24 to pass into the inner lumen of the tubular fastener 22.

Now with reference to FIG. 2B, certain inner components of theprosthetic heart valve 20 are illustrated, which can also be seen ingreater detail in FIGS. 6-9. The fastener 22 illustrated is located inone of the cusps 46 of the valve 20, and a section through one of thecommissures 42 would be somewhat different. The sealing ring 30comprises an inner sponge member 50 having a fabric cover 52. In apreferred embodiment, an annular planar retention disc 54 is assembledwith the sealing ring 30. As will be explained below, the retention disc54 is positioned on top of the sponge member 50 and has a plurality ofapertures for holding the fasteners 22. It should be understood that theretention disc 54 could also have an undulating shape to match the uppersurface of non-planar sealing rings, such as the sewing ring shape ofvalve models 3000-3300 and 7300 made by Edwards Lifesciences of Irvine,Calif.

An inner wall of the sealing ring 30 attaches to a stent member 60 alsohaving a fabric covering 62. At the top of the stent member 60, thefabric covering is rolled into a sewing tab 64. An outer edge of one ofthe valve leaflets 44 is sandwiched between the top edge of the stentmember 60 including the sewing tab 64 and a wireform 66 having a fabriccovering 68. Sutures hold the components together.

FIG. 3 is a plan view of an exemplary annuloplasty ring 70 havingtubular side entry fasteners 72 embedded in a pliant sealing edge, whileFIG. 3A is an enlarged view of a fastener and FIG. 3B is a cross-sectiontherethrough. Annuloplasty rings can be continuous or open, rigid,semi-rigid, or more flexible, and the present application contemplatesall types. The annuloplasty ring 70 illustrated in FIG. 3 is configuredfor implant at a mitral annulus, and as such has a plan view as seenwhich is generally oval and slightly D-shaped with a more pronouncedcurve along the lower or posterior segment 74 as opposed to the upper oranterior segment 76. The outer ends of the relatively straight anteriorsegment 76 approximately corresponds to the expected location of fibroustrigones around the mitral valve annulus on either side of the anteriorleaflet. In illustrated embodiment, there are eleven knotless suturefasteners 72 distributed around the periphery of the annuloplasty ring70. Desirably, fasteners 72 are located adjacent the trigones, and oneis located adjacent the midpoint of the posterior segment 74, with therest being distributed evenly therebetween.

FIG. 3A illustrates the suture fastener 72 embedded within a pliantsealing edge of the annuloplasty ring 70. The annuloplasty ring 70comprises an inner core 80, typically metallic, surrounded by a siliconesleeve 82 which, in turn, is enclosed within a fabric cover 84. Theillustrated inner core 80 comprises a plurality of concentric bands,though other rigid and semi-rigid structures such as a solid titaniumring are often utilized. A pliant sealing edge may comprise a portion ofthe silicone sleeve 82 and fabric cover 84 which project outward fromthe inner core 80. It should be understood that the materials of thepliant sealing edge may be other than silicone and fabric, such as allfabric for example. If the ring is entirely flexible, such as being madeentirely of a silicone band surrounded by a fabric cover, then theentire ring can be considered the sealing edge and the suture fastenerscan be positioned anywhere through the ring. The sealing edge may beconfigured like the pliant outer edges of conventional annuloplastyrings, such as with rolled fabric or fabric-covered silicone, but nosutures are passed through it and thus it is not called a sewing edge.

Each fastener 72 has an open state which permits a suture to slideaxially therethrough, and a closed or deployed state which preventsaxial movement of the suture in at least one direction. Moreparticularly, the exemplary knotless suture fastener 72 has a generallytubular outer wall 86 defining a lumen 88 having a diameter extendingfrom a proximal end 90 a to a distal end 90 b. The outer wall 86 isinterrupted by a collapsible wall structure for contacting and holding asuture length within the lumen 88. The suture enters the fastener 72through a vertical slit 92 in the outer periphery of the annuloplastyring 70 and a vertical opening 93 in the fastener. As will be furtherdescribed below, the collapsible wall structure has an open state thatdoes not restrict relative movement between the fastener 72 and a suturetherein and is biased toward a closed or deployed state that restrictsdistal movement of a suture through the fastener without preventingproximal movement.

As seen in FIG. 3B, the proximal end 90 of the suture fastener 72projects slightly above a proximal face 94 of the annuloplasty ring 70.The distal end 92 desirably lies flush with or slightly above the distalface 96, as shown, though it may project slightly below the distal face96. The distance that the fastener 72 can project from either facedepend somewhat on the particular valve annulus at which the cardiacimplant is secured, but typically neither end of the fastener extendsmore than 3 mm above or below the implant.

FIG. 3B shows an exemplary configuration for securing the suturefastener 72 within the annuloplasty ring 70. In particular, a pluralityof attachment threads 98 loop through small holes 100 at the proximaland distal ends 34, 36 and tie off through the fabric cover 84. Thetubular suture fastener 72 may first be pushed through the soft sealingedge using a leading punch or awl-type of device (not shown). Otherconfigurations for securing the suture fastener 72 in the illustratedposition within the annuloplasty ring 70 are contemplated. For example,flanges on either end may be provided which retained the fastener inposition, one of the flanges being spring-loaded so that it may first beretracted for insertion into the soft annuloplasty ring. Alternatively,the fastener may be more rigidly connected to the inner core 80 usingwelding or similar expedient.

In a preferred embodiment, an annular planar retention disc 102 isassembled within the annuloplasty ring 70 for securing the suturefasteners 72. The retention disc 102 may be positioned on top of theinner core 80 and within the fabric cover 84, and includes a pluralityof apertures for receiving and retaining the suture fasteners 72. Byvirtue of the retention disc 102, the suture fasteners 72 may be securedwithin the annuloplasty ring 70 without using the attachment threads 98.The retention disc 102 is desirably a polymer, such as Delrin.

FIGS. 4A-4C are enlarged and sectional views showing an exemplarytubular side entry fastener 110 and a retention pin 112 isolated fromthe cardiac implants for clarity. The retention pin 112 has a proximalgripping portion 113 and a distal hypotube 114 that resides within andmaintains the fastener 110 open, and when removed, permits the fastenerto clamp onto the sutures, as will be explained. The illustratedfastener 110 is particularly well-suited to receiving a retention pin112 as shown, though other retention members such as bifurcated clips,flexible cables, staples, etc. may be used. The term, “retention member”is used herein to refer to these variants, though retention pin may beused for the sake of clarity.

The suture fastener 110 is preferably formed from an elastic materialsuch as a memory material like Nitinol having a collapsible wallstructure comprising a pair of tabs 116 cut into a tubular outer wall118 each of which extends into an inner lumen in the closed state. Eachsuture fastener 110 further includes a window 120 in the tubular outerwall 118 opposite each of the tabs 116 and into which the respectiveopposed tab extends in the closed state of the fastener. Moreparticularly, an upper tab 116 a extends into an upper window 120 thatis opposite from the upper tab. A lower tab 116 b extends into a lowerwindow that is formed in the upper tab 116 a and not visible in thedrawings. The lower window resembles a similar window 122 formed in thelower tab 116 b (as shown in an alternative configuration of the tubularfastener in FIG. 4D).

The suture fastener 152 may be formed from suitable biocompatiblematerial, including, for example, Nickel-Titanium or other shape-memoryalloys, stainless steel, titanium, other metals, various plastics, andother biologically-compatible materials. The axial height of the suturefastener 110 may be up to about 3 mm. The diameter of the tubular wall118 may vary depending on suture size, but is typically between about1-2 mm. Braided sutures are used to attach prosthetic heart valves toannuluses as opposed to monofilament polypropylene sutures (e.g.,Prolene) which are used in other surgical environments. In the UnitedStates, suture diameter is represented on a scale descending from 10 to1, and then descending again from 1-0 to 12-0. A number 9 suture is0.0012 in (0.03 mm) in diameter, while the smallest, number 12-0, issmaller in diameter than a human hair. Although suture size depends onsurgeon preference, typically 1-0 or 2-0 braided sutures are used. Inone embodiment, if 1-0 sutures are used the diameter of the suturefastener 110 is approximately 1.5 mm, while if 2-0 sutures are used thediameter is 1.0 mm.

Two rows of small holes 124 are provided around the circumference of theouter wall 118 adjacent the proximal and distal ends thereof forsuturing the fastener 110 to a cardiac implant. Alternatively, aretention disc such as shown at 54 in FIG. 2B or at 102 in FIG. 3B maybe used to secure the fastener 110 to the cardiac implants. Stillfurther, FIG. 4D illustrates an alternative tubular side entry suturefastener 125 that is in most respects similar to the fastener 110, butincludes an upper flange 126 wider than the tubular body and sized toretain the fastener 124 on the cardiac implant. That is, sutures areanchored to the anatomical structure below the implant, and pass upwardthrough the suture fastener 124. By virtue of the width of the flange126, the fastener 124 is prevented from pulling through the cardiacimplant, and thus the implant is effectively sandwiched between theanatomical structure and the flange 126. Alternatively, a plurality ofsuture holes 128 may be provided in the flange 126 to supplement theattachment.

Each of the fasteners 110 receives a hypotube 114 on the retention pin112 in its lumen to hold the resilient tabs 116 outward into their openstate. In this regard, each retention pin 112 is preferablypre-assembled and packaged along with the cardiac implant to avoid theprocess of connecting each of the retention pins to an associatedfastener in the operating room. The hypotube 114 has an outer diameterthat is slightly smaller than the inner diameter of the tubular wall ofthe suture fastener 110, and as such, when inserted in the lumen, thehypotube maintains the tabs 116 flexed outward (straightened) in theaxial positions shown in FIG. 4A. Implant attachment sutures 132 maythen be passed through an axial opening 134 in the fastener 110 andthrough an axial slot 136 in the retention pin 112. As mentionedpreviously, the axial opening 134 and axial slot 136 line up, as in FIG.4C, and both are aligned with the corresponding slit formed in thesealing ring or sealing edge of the cardiac implant (such as slit 32seen in FIG. 1A).

It should be noted that forming the hypotube 114 of the retention pin112 to be tubular with an axial slot 136 leading to an inner lumen isonly one way to ensure that a suture can enter the lumen of the fastener110. That is, other configurations include a semi-cylindrical hypotube114 that occupies space within the fastener 110 to hold the tabs 116outward while still leaving space for sutures within the fastener lumen.Various configurations are possible, the requirement being only that behypotube 114 is other than solid and cylindrical.

The hypotube 114 is desirably made of surgical grade metal such asstainless steel so that it maintains its diameter against the inwardforce of the fastener tabs 116 over potentially long periods of storagetime. Further, a metal will better resist gouging by the tabs and cantherefore be easily removed from within the fasteners 110. It will beunderstood by the reader that the hypotube 114 cannot simply be inserteddownward through the fastener 110, but instead a thin assembly shaft(not shown) of the same size is first inserted upward to force the tabs116 outward. Subsequently, the hypotube 114 is pushed downward throughfastener 110 so as to displace the assembly shaft without permitting thetabs 116 to spring inward. This can be done manually, but preferably aloading fixture to center the cooperating elements is used. An exemplaryloading fixture will be described below.

In use of the suture fastener 110, as seen in FIGS. 4A and 4B, the tabs116 are spring-biased inward and, upon removal of the hypotube 114,clamp onto and restrict distal (downward) movement of a suture 132through the fastener without preventing proximal (upward) movement. Thatis, the tabs 116 in the closed state permit distal (downward) movementof the cardiac implant on the sutures while preventing proximal (upward)movement. Consequently, whether deployed or not, the suture fasteners110 permit a user to parachute a cardiac implant down an array ofpre-installed sutures until the implant sits on the annulus, at whichpoint the suture fasteners prevent the implant from moving upward fromthe annulus.

Another option for the suture fasteners disclosed herein (such as thetubular fastener 110) is to provide a plastically-deformable portion inaddition to the spring-biased tabs. For example, the upper end of thetubular wall 118 of the suture fastener 110 could be formed of materialthat is capable of plastic deformation. A crimping tool or other suchdevice can then be lowered to the implant site and used to flatten thetop end of the fastener on the anchoring sutures 132 to supplement thespring-biased tabs 116.

FIGS. 5A and 5B show the tubular side entry fasteners 110 embedded in asealing ring 140 of a prosthetic heart valve 142, before and afterdeployment. That is, the retention pins 112 are initially in placewithin the fasteners 110, as in FIG. 5A. Pulling the retention pins 112upward deploys the tabs 116 in the fasteners 110, thus engaging thesutures 132. To help avoid a multitude of small retention pins 112 inthe surgical site, one or more may be coupled together with tethers orsutures 144. For example, every three of the retention pins 112 may becoupled together so that they are much less likely to be misplaced.

In one preferred sequence, the surgeon advances the cardiac implant(such as heart valve 142) until it seats at the target annulus. Duringthis advancement, the free ends of all of the attachment sutures 132 arecontrolled to prevent slack. Once the cardiac implant reaches the targetannulus, the surgeon applies a desired amount of tension to each pair ofthe attachment sutures 132, and simultaneously displaces thecorresponding retention pin 112 in a proximal direction, as seen inFIGS. 4B and 5B to deploy the fasteners 110. Each pair of attachmentsutures 132 is then severed close to the proximal end of the respectivesuture fastener 110. This can be done with scissors, sheared by theretention pin 112 (e.g., between the end of the tube and the suturefastener 110), sheared by a sharp edge provided on the suture fastener110 (not shown), or any combination thereof.

FIGS. 6-9 illustrate an exemplary assembly configuration for aprosthetic heart valve having the side entry tubular fasteners disclosedherein. FIG. 6 is an exploded perspective showing an inner stent member150 above an annular retention disc 152 which, in turn, is above anannular sealing ring sponge 154. Again, the annular retention disc 152may be planar, as shown, or have an undulating contour to match thecontour of the sponge 154 which, in turn, is shaped to better match theanatomy such as the aortic annulus. The stent member 150 defines anundulating shape having upwardly projecting commissure posts 156 inbetween downwardly arcing cusps 158. In preferred embodiments, the stentmember 150 includes a polymer inner band 160 which defines thecommissure posts 156, and a metallic outer band 162 which matches theshape of the inner band except for being truncated short of the top ofthe commissure posts. The sponge 154 may be formed of any pliantmaterial such as silicone or fabric, and serves to provide a softsealing member surrounding the inflow end of the heart valve to preventparavalvular leakage. The retention disc 152 features a series ofapertures 164 distributed evenly around its circumference and proximateits outer peripheral edge 166. Each of the apertures 164 opens to theperipheral edge 166 through a short channel 168.

FIG. 7A is a perspective view of the retention disc 152 having theapertures 164 around its periphery. A series of assembled side entryfasteners 110 and retention pins 112 are shown being inserted into theapertures 164. As mentioned above, the vertical slits in the side of thefasteners 110 and hypotubes 114 align and are oriented so as to registerwith the channels 168 in each of the apertures 164. In this regard,anti-rotation structures may be provided on the fasteners 110, pins 112,and apertures 164 to ensure that these side openings align. For example,a flat portion extending the length of the hypotube 114 may registerwith a flat within the lumen of the fastener 110, and the exterior wallof the fastener may include a flat that registers with a similar flatformed in the corresponding aperture 164. Alternatively, ribs andchannels may be formed on the opposing faces of these components. Ofcourse, those of skill in the art will understand that there are anumber of ways to ensure rotational registration of the side openings.

FIG. 7B shows the retention disc 152 of FIG. 7A above the sealing ringsponge 154 with the tubular fasteners 110 extending within outerrecesses 170 formed within the sponge. With reference back to FIG. 6,the sponge 154 features a series of the grooves or recesses 170 evenlydistributed around its periphery and opening both to its upper face andits outer wall. The outer diameter of the retention disc 152 isapproximately equal to the outer diameter of the sponge 154, such thatthe downwardly projecting fasteners 110 fit closely within the recesses170.

Next, FIG. 7C shows the components from FIG. 7B with a tubular fabricpiece 172 disposed within the annular sponge 154. The fabric piece 172features a series of axial slits 174 formed in both its upper 176 andlower 178 edges. The fabric piece 172 is then wrapped around the top andbottom of the assembled retention disc 152 and sponge 154 and sewnthereto. The slits 174 enable the fabric to go between the upstandingretention pins 112.

FIG. 7D illustrates a stent subassembly 180 including the componentsshown exploded in FIG. 6 covered and joined together with fabric. Moreparticularly, the structure formed by wrapping the fabric piece 172around the assembly in FIG. 7C defines a sealing ring 182. The stentmember 150 from FIG. 6 is then covered with fabric and attached to theinner wall of the sealing ring 182.

Now with reference to FIG. 8, a leaflet subassembly 190 comprises afabric-covered undulating wireform 192 having flexible leaflets 194attached thereto. The wireform 192 defines narrow arcuateupwardly-projecting commissure regions 196 in betweendownwardly-projecting arcuate cusp. The leaflets 194 extend inward fromthe surrounding wireform 192 into a flow orifice defined thereby. In apreferred embodiment, there are three bioprosthetic leaflets 192 thatcurve toward the outflow direction and “coapt” in the middle of thevalve orifice to ensure one-way flow through the valve. FIG. 8A is asectional view through one edge of the leaflet subassembly showing afabric covering 200 around the wireform 192 that extends outward thereonand is folded into a sewing tab 202. The outer edge 204 of each of theleaflets 194 extends under the sewing tab 202 and may be initially sewnthereto and, as seen in FIG. 9A, is then sandwiched and sewn between thesewing tab 202 and a sewing tab 206 at the upper end of thefabric-covered stent member 150.

FIG. 9 illustrates a completed prosthetic heart valve 210 having thetubular side entry fasteners and corresponding retention pins 112 aroundthe periphery of the sealing ring 182. The small vertical slits 212 inthe outer edge of the sealing ring 182 are formed by the slits 174 inthe fabric piece 172 of the sealing ring (see FIG. 7C). The slits 212are located at the circumferential location of the fasteners 110, which,though not shown, are positioned in the recesses 170 of the sealing ringsponge 154.

FIG. 9A is a sectional view through the heart valve 210 showing theposition of one of the tubular side entry fasteners 110 within thesealing ring 182. The slit 212 is indicated by fabric that may bewrapped around the inside walls of each of the recesses 170.Alternatively, the slits may be left alone on the outer extent of eachof the recesses 170, so that the sectional view would show an outerportion of the sponge 154. There are various ways to wrap the fabricpiece 172 around the sponge 154, as long as a slit or opening is leftleading to the fastener 110.

Finally, FIG. 9B is an enlarged view of one of the side entry fasteners110 and its accompanying retention pin 112 looking directly radiallyinward through the vertical slit in the sealing ring 182. It should benoted that the retention pin 112 also includes an axial slot 214 so thatthe attachment sutures 132 can be passed to the interior of the entirestructure.

The present application also contemplates a side-entry suture fastener250 that has bifurcated clamping halves, as shown in FIGS. 10-15.

With reference to FIGS. 10A and 10B, the fastener 250 provides a suturelocking retainer which eliminates the need for tying knots in surgicalsutures. The suture fastener 250 includes a bifurcated locking clamp 252having an axial hinge 254, as seen in FIG. 12. The locking clamp 252 canbe plastic and molded, and has two substantially identical halves 256 a,256 b separated by a variable-sized slot 258. The two halves 256 a, 256b are biased together by at least one exterior “C” clip 260. The axialhinge 254 is desirably a “living hinge” formed in the molded part alongone side so that the halves 256 a, 256 b can pivot apart to vary thesize of the slot 258 and form an opening on the side opposite from thehinge in which sutures can be inserted. Alternatively, a true hinge maybe provided between the two halves 256 a, 256 b.

As with the earlier embodiments, an overall exemplary size of the devicecan be 2 mm in height and diameter, or smaller. The initial design shownhere is based on 2-0 sutures, which are commonly used in valvereplacement procedures. Furthermore, the dimensions and parameters formaterials described above for the earlier embodiments also apply to thefastener 250 of FIGS. 10-15.

As seen in FIG. 11, each half 256 includes a semi-cylindrical middlerecess 262 between two outwardly-projecting end flanges 264. When thetwo halves 256 are brought together, they define a spool shape. As seenin FIGS. 10A, 10B, the C-clips 260 are received in the recess 262 withtheir open ends 266 flanking the variable-sized slot 258 and directlyopposed to the hinge 254. The end flanges 264 hold the C-clips 260 inplace.

One or more of the C-clips 260 seen in FIG. 13A are placed around theclamp and sized such that they apply a force which acts to close theclamp 252 and close or eliminate the slot 258, thus clamping ontosutures that pass through the slot. The C-clip(s) 260 thus providebiasing members positioned on the outside of the locking clamp 252having a relaxed size that, in the absence of any other object in theslot 258, urges the inner surfaces of the clamp halves 256 together suchthat the slot has a width smaller than the suture thickness. In analternative configuration, a section of tube with a slit (forming a “C”in cross section) could replace the array of “C” clips. Indeed, theterm, “biasing member” should be understood to refer to one or moreelements as described herein.

The C-Clips 260 would most likely be formed from Nitinol wire, althoughother materials such as stainless steel should not be excluded. For theexemplary embodiment shown, the C-clips 260 are formed from 0.008″diameter wire and have an outside diameter of 0.079″ (2 mm). Theillustrated embodiment incorporates five C-clips 260, though additionalC-clips 260 could be added to increase the clamping force. Additionally,the clamping force can be increased significantly by small increases inthe wire diameter of the C-clips 260. The bending stiffness of acircular wire is proportional to the 4^(th) power of its diameter, andso increasing the wire diameter from only 0.008″ to 0.010″ increases theclamping force by a factor of 2.4, while an increase to 0.012″ wouldresult in a five-fold increase in clamping force. Thus by changing thenumber of C-Clips and their wire diameters, large changes in theclamping force can be realized with minimal impact on the devicediameter and small changes in device height.

FIG. 13B shows an alternative biasing member or C-clip 290 in the formof a short tubular collar 292 having an axial split on one sideterminating in free ends 294 separated across a slot or gap. Thecross-section of the collar 292 is a C-shape, and the axial height isdesirably about the same as the height of the stack of C-clips 260 seenin FIG. 10B, or the distance between the end flanges 264 of thebifurcated locking clamp 252 as seen in FIG. 11. The C-clip 290 is alsodesirably made of Nitinol (binary alloy of primarily Nickel andTitanium), though NiTiCo (ternary alloy of primarily Nickel, Titaniumand Cobalt) is stiffer than “regular” Nitinol and hence allows a smalleroverall diameter and height of the device.

The NiTiCo is up to about 80% stiffer than Nitinol, so the math showsthat the diameter of the NiTiCo collar can be about 21% less to achievethe same force (because force roughly goes with wall thickness to the3^(rd)). As an example, that could reduce the OD of the collar from 2.0mm for Nitinol to 1.58 mm for NiTiCo. Or, for the same diameter theNiTiCo collar could be ˜80% shorter, since the force is linear withlength.

FIGS. 14A-14D illustrate a sequence of operation of the side entrysuture fastener 250. First, the assembled fastener 250 includes theaforementioned components as well as a retention pin 270 having an upperhead 271 (again, the term “retention pin” should not be consideredlimiting, and is shorthand for a more generic “retention member.”).Prior to use, the two halves 256 a, 256 b are forced apart so that theretention pin 270 may be inserted into a retention pin channel 272, asseen best in FIG. 12. The retention pin channel 272 is defined betweenthe axial hinge 254 and an axially-oriented retainer rib 274 formed onone or both halves 256 and extending into the slot 258. Release of thetwo halves 256 permits the C-clips 260 to force the two halves to pivottoward one another and clamp onto the retention pin 270. Preferably, thefastener 250 is pre-assembled by the manufacturer, i.e. the retentionpin 270 and C-clips 260 are pre-assembled with the clamp halves 256 a,256 b. The presence of the retention pin 270 holds open the two halves256 a, 256 b so that the slot 258 widens into the opening opposite thehinge 254 into which one or more sutures 280 can be inserted.

As a first step in the process of deployment, the surgeon laterallydisplaces one or more sutures 280 toward one of the suture lockingdevices 250, as seen in FIG. 14A (and as depicted for the firstembodiment in FIG. 1A). As mentioned, the slot 258 defines an openinginto which the sutures 280 are received. As seen in FIG. 14B, thesurgeon then tensions the sutures 280 while the prosthetic heart valvesealing ring or annuloplasty ring to which the fastener attaches isseated against the native annulus. In FIG. 14C, the retention pin 270 isremoved, thus allowing the C-clips 260 to force closed the oppositehalves 256 a, 256 b of the clamp 252, thus clamping the suture(s) 280therebetween, as seen in FIG. 14D.

Alternatively, as mentioned above, the fastener 250 may be deployedprior to the valve or annuloplasty ring being advanced to the annulus,as the exemplary fastener permits one-way travel of the suturestherethrough. With reference back to FIG. 12, the inner faces of one orpreferably both of the device halves 256 a, 256 b include a plurality ofgrip members 282 that help prevent relative movement between thedeployed fastener 250 and the sutures 280. More particularly, the gripmembers 282 prevent relative longitudinal movement between the fastener250 and sutures 280 in only one direction. For example, the grip members282 are formed as wedges with a ramp angled in one axial direction, inthe illustrated embodiment the wedges are angled upward. Due to theirorientation, and after the fastener 250 has been deployed, the sutures280 would be prevented from moving relatively downward, but could bepulled through upward. Stated another way, the fastener 250 could beslid downward on the sutures, but not upward. This configuration enablesthe surgeon to increase the tension on the sutures 280 once the fastener250 is closed, but loosening of the sutures would be inhibited.Desirably, both inner faces of the device halves 256 a, 256 b include anaxial bar 284 that helps retain the sutures 280 within the slot 258. Asseen in FIG. 14D, the bars 284 extend sufficiently inward toward eachother so as to close and present a barrier to lateral escape of thesutures 280.

FIG. 15 illustrates how the suture(s) 280 can be tensioned further afterdeployment of the fastener 250. It will be noted that only one suture280 is shown in this view to emphasize that one or more can be securedby the fastener 250. The individual grip members 282 could be axiallyoffset on the two halves 256 a, 256 b to enhance their frictional holdon the suture(s) 280. In other words, deploying the fastener 250 createsa serpentine path for the suture(s) 280 between the alternating gripmembers 282. The cross-section of the slot 258 shows the offset suturegrips 282, which thus act as a “one way” ratchet that allows for furthertensioning of the suture(s) after deployment of the device, but resistloosening of the sutures.

FIG. 16A is a perspective view of a flexible leaflet prosthetic heartvalve 300 having a number of the split side entry fasteners 302distributed around its sealing ring 304. Each of the fasteners 302, asseen in the sectional view of FIG. 16B sits on top of the sealing ring304, rather than being embedded within. Although not shown, thefasteners 302 may be secured to the sealing ring 304 with sutures,adhesives, or other similar expedient. The sealing ring 304 isconfigured as described above to have vertical slits 306 at thecircumferential location of each one of the fasteners 302. As seen inFIG. 16B, each fastener 302 is positioned to extend partly over thecorresponding slit 306 so that sutures can be laterally displacedthrough the slit 306 and into the slot within the fastener. Positioningthe fasteners 302 partly over the slit 306 and partly over a solidportion of the sealing ring 304 helps prevent the fastener from beingpulled through the slits.

FIG. 17A is an enlarged view of one of the side entry fasteners 302looking directly radially inward through the vertical slit 306 in thesealing ring 304 and prior to deployment, while FIG. 17B shows thefastener 302 after deployment by removal of a retention pin 308. It willbe appreciated that the sealing ring 304 is also representative ofannuloplasty ring.

In an alternative embodiment depicted in phantom in FIG. 16B, each ofthe fasteners 302 sits on top of the sealing ring 304 and is attachedonly on a radially inner corner such that it can be pivoted upward;i.e., the fastener 302 behaves as if it was hinged to the sealing ring304 at its bottom inner corner (opposite the opening in the fastener).When pivoted upward, a pair of sutures could be placed through the slit306 in the sealing ring 304 adjacent to the flipped-back fastener 302,and then the fastener is then hinged back flat against the sealing ring,capturing the sutures.

FIG. 18A is a perspective view of a hybrid prosthetic heart valve 310implanted at an aortic annulus AA and illustrating three of the splitside entry fasteners 312 positioned above a sealing ring 314. Thefasteners 312 may be attached to the sealing ring 314 as describedabove. The aortic prosthetic heart valve 310 is a hybrid type with avalve member 316 having an expandable anchoring skirt 318 attached toand projecting from an inflow end of the valve below the aortic annulusAA. A balloon catheter may be used to expand the anchoring skirt 318against the surrounding subannular tissue. Of course, other expansiondevices may be used, and the skirt 318 is thus termed“plastically-expandable” to encompass various ways of expansion.

Further details of such a hybrid prosthetic heart valve 310 and anassociated delivery system can be found in U.S. Patent Publication No.2012/0065729 to Pintor, et al., filed Jun. 23, 2011 and expresslyincorporated herein. In the Pintor disclosure, three guide sutures arepre-installed at the aortic annulus and threaded through cusp regions ofthe prosthetic heart valve. The three guide sutures are primarily usedto orient the heart valve rotationally within the aortic annulus suchthat the leaflets register with the surrounding coronary ostia (in twoof the three coronary sinuses). However, the guide sutures alsosupplement the anchoring function of the expandable anchoring skirt 318.There remains a problem of the time it takes to tie off each of thethree guide sutures, which problem is alleviated by the side entryknotless suture fasteners 312, as described in the present application.

FIG. 18B is a top plan view of the prosthetic heart valve showingdistribution of the split fasteners 312 at the valve cusps 320. Thereare desirably three suture fasteners 312 on the sealing ring 314 locatedin the middle of the valve member cusps 136. Each of the side entryfasteners 312 is circumferentially aligned with a slit 322 formed in thesealing ring 314, such as described above for other embodiments.Preferably, the sealing ring 314 has a relatively flat or constantelevation proximal (outflow) face, and an undulating distal (inflow)face that is shaped to match the undulating contour of the aortic valveannulus. In the middle of the cusps 320, the sealing ring 314 has amaximum thickness which provides more material for securing anchoringsutures with the suture fasteners 312.

The heart valve 310 is mounted on a holder and handle assembly and thethree pairs of anchoring sutures are inserted through the slits 322 suchthat they may be engaged by the fasteners 312. The valve 310 is thenadvanced down the anchoring sutures until the distal face of the sealingring 314 contacts the aortic annulus AA, in the position shown in FIG.18A. The prosthetic heart valve sealing ring 314 seats on the inwardlyprojecting supra-annular shelf of the aortic annulus AA, and theanchoring skirt 318 is expanded by the balloon catheter in thesubannular region. Each pair of anchoring sutures can be properlytensioned by the surgeon just prior to converting the suture fasteners312 from their open states to their closed states. Alternatively, thefasteners 312 are capable of sliding down the anchoring sutures afterbeing deployed and prevent the valve from pulling upward away from theannulus.

FIG. 19 is a perspective view of an alternative split side entryfastener 330 having an enlarged upper flange 332 with sewing holes 334therein. As seen in FIGS. 20A and 20B, the side entry fasteners 330maybe embedded in a sealing ring 340 of a heart valve, similar to thosedescribed above. Alternatively, the sealing ring 340 is representativeof the sealing edge of an annuloplasty ring.

As described above, the sealing ring 340 features a plurality of radialslits 342 therein which opened to the variable-sized mouth 344 of thebifurcated fastener 330. As before, a plurality of C-clips 346 bias thetwo halves of the bifurcated fastener 330 toward each other, and aretention pin 348 maintains the mouth 344 open for introduction ofanchoring sutures 350. A sequence of displacing the anchoring sutures350 into the slit 342 and within the mouth 344 of the fastener 330followed by removal of the retention pin 348 is shown in FIGS. 20A and20B. Stitches 352 through the sewing holes 334 may be used to secure theupper flange 332 of the fastener 332 the sealing ring 340.Alternatively, the flange 332 may be solid without the sewing holes andbe wide enough to prevent the fastener from pulling through the slit342.

FIGS. 21A-21D illustrate several components and steps in assembling aprosthetic heart valve 360 having the embedded side entry fasteners 330of FIGS. 19-20. In FIG. 21A, an annular, pliant sponge 362 similar tothose described is shown exploded from a tubular fabric piece 363. Thefabric piece 363 has a plurality of vertical slits 364 therein each ofwhich correspond to a recess 366 in the outer edge of the sponge 362.

FIG. 21B shows the sponge 360 and fabric piece 363 assembled into asealing ring 368, wherein the fabric piece has been wrapped around thesponge and sewn thereto. Each of the slits 364 is seen on the outer edgeof the sealing ring 368. A plurality of the side entry fasteners 330 areshown elevated above the sealing ring 368, with dotted lines indicatingthat they will be inserted through the slits 364 to fit in the recesses366 of the sponge 362. The upper flanges 332 of the fasteners 330 remainon top of the sealing ring 368, and may be attached thereto with suturesas explained above. Tethers 370 are shown connecting the retention pins348 of the three fasteners 330 shown.

FIG. 21C shows the completed sealing ring 368 having the fasteners 330embedded around its periphery. As shown, there are tethers 370connecting the retention pins 348 of each of the three fasteners 330,and there are a total of 18 fasteners. Of course, the number offasteners 330 can be adjusted, and the tethers 370 can connect anynumber of retention pins 348, the number shown being exemplary only.

FIG. 21C also shows a cloth-covered stent member 374 above the sealingring 368, with a wireform subassembly 376 above that. Connecting thesecomponents as was described earlier results in the assembled heart valve360 seen in FIG. 21D. Providing the tethers 370 connecting at least twoof the fasteners 330 helps reduce the possibility of losing one of theretention pins 348. That is, as the retention pins 348 are removed fromthe fasteners 330, they are tethered to other of the pins so as to bemore difficult to misplace.

FIGS. 22, 23 and 23A illustrate an exemplary suture fastener loadingfixture 400 of the present application capable of rapidly loading anumber of the suture fasteners 110 of FIGS. 4-9 onto the correspondingretention pins 112. In the illustrated embodiment, there are 12 loadstations in the loading fixture which may be sufficient to secure asurgical heart valve or an annuloplasty ring to an annulus. Of course,more or fewer load stations may be provided in the fixture 400 dependingon the application.

The loading fixture 400 includes a lower base member 404, anintermediate platform 406, and an upper cover 408 rotatable about theplatform. The base member 404 defines a plurality of load stations 410circumferentially spaced around a central axis, each includingindependently moving blocks 412 having thin mandrels 414 projectingupward therefrom. As seen in the sectional view of FIG. 23A, each block412 is supported from underneath by a spring 416 centered over a spindle418 in a cavity 420 of the base member 404. Each load station 410further includes a cylinder 422 on the intermediate platform 406centered over the block 412 and mandrel 414. As seen in FIG. 23A, eachcylinder 422 defines a receptacle 424 over a through hole (not numbered)sized so that the mandrel 414 projects upward from the block 412 intothe receptacle. The mandrel 414 has an outer diameter that isapproximately equal to the luminal diameter of the suture fasteners 110,and the receptacles 424 have an axial height slightly greater than thelength of the suture fasteners, such that the load stations 410 can eachbe loaded with a suture fastener on the mandrel and within thereceptacle, as seen best in FIG. 25A.

The intermediate platform 406 and upper cover 408 are secured over thebase member 404 using a central bolt 426. Removal of the bolt 426, uppercover 408, and intermediate platform 406 exposes the plurality ofupstanding mandrels 414 onto which suture fasteners 110 can be manuallyplaced. The intermediate platform 406 goes over the base member 404 andthe two are keyed together to prevent relative rotation. The upper cover408 is then secured over the intermediate platform 406 with the bolt426. The upper cover 408 cooperates with the intermediate platform 406for step-wise rotation thereover, as will be described.

Each load station 410 further includes a lead-in cavity 430 formed inthe upper cover 408 as seen in FIGS. 23/23A sized to closely receive theretention pins 112. Preferably, there is only one lead-in cavity 430 inthe cover 408 which the user can rotate around the axis of the generallycylindrical loading fixture 400 to register with different load stations410. In the illustrated embodiment the lead-in cavity 430 defines agradual inward taper to help center the distal end of the retention pins112.

FIG. 24 is a perspective view of the loading fixture 400, while FIGS. 25and 25A are sectional views through the load station 410 showing aretention pin 112 entering the lead-in cavity 430. The hypotube 114projects distally from the pin 112 prior to loading with a suturefastener. As will be shown, inserting the retention pin 112 into eachload station 410 enables transfer of one of the suture fasteners 110 tothe hypotube 114.

FIGS. 26A-26C illustrates several steps in using the load stations 410to load a suture fastener 110 onto the retention pin 112. FIG. 26Aillustrates the retention pin 112 just prior to bottoming out within thelead-in cavity 430. As mentioned above, the cooperation between thecavity 430 and the distal end of the retention pin 112 desirably centersthe projecting hypotube 114 over the load station receptacle 424. Asuture fastener 110 is shown within the receptacle 424 mounted on themandrel 414. The top ends of the suture fastener 110 and mandrel 414 arepositioned just below the upper opening to the receptacle 424 such thatthe upper cover 408 can freely rotate over the tops of the cylinders422, as seen in FIG. 22. That is, the upper cover 408 is in contact withthe flat and substantially continuous tops of the cylinders 422.Desirably, interacting features such as small molded bumps or the like(not shown) are provided in the upper cover 408 and intermediateplatform 406 so that the lead-in cavity 430 can “click” from loadstation 410 to load station in a step-wise manner.

FIG. 26B shows the retention pin 112 bottoming out within the lead-incavity 430. As mentioned, the projecting hypotube 114 has the samediameter as the mandrel 414, both of which fit closely within the lumenof the suture fastener 110. Prior to FIG. 26B, the mandrel 414 maintainsthe collapsible wall structure on the suture fastener 110 in an openstate. As the hypotube 114 descends, it displaces the mandrel 414 fromwithin the suture fastener 110, pushing the mandrel 414 and the attachedblock 412 downward against the force of the spring 416. The receptacle424 has a bottom floor (not numbered) that limits downward movement ofthe suture fastener 110. Eventually, the hypotube 114 advances just farenough to displace the mandrel 414 from within the fastener. Thedistance that the hypotube 114 projects from the gripping portion 113 ofthe retention pin 112 is approximately equal to the height of thereceptacle 424 such that the hypotube ends within or at the bottom endof the fastener 110 when the retention pin 112 bottoms out within thelead-in cavity 430.

It should be noted that this loading procedure is necessitated by theone-way nature of the collapsible wall structure on the suture fastener110. That is, each suture fastener 110 may be easily pushed downwardonto the mandrel 414, which forces the collapsible wall structureoutward. However, the fasteners 110 could not otherwise be pushed upwarddirectly onto the hypotube 114 because of the configuration of thecollapsible wall structure. This will be clear from inspection of theexemplary fasteners 110 as described above with reference to FIGS.4A-4D, wherein the collapsible wall structure comprises theoppositely-directed tabs 116 a, 116 b cut into the tubular outer wall118 and extending into the central lumen in the closed state of thefastener.

In any event, displacing the mandrel 414 from within the fasteners 110transfers the inward force exerted by the elastic tabs 116 to thehypotube 114, which temporarily secures the fastener onto the retentionpin 112. Additionally, after expulsion of the mandrel 414 from thefastener 110, the spring 416 pushes the block 412 and mandrel 414upward, thus elevating the gripping portion 113 of the retention pin 112above the level of the cover 408, enabling easy removal. As seen in FIG.26C, the retention pin 112 may then be lifted free of the load fixture400 for assembly into a cardiac implant, with the suture fastener 110held on the projecting hypotube 114.

In one embodiment, the fastener loading fixture 400 includes the samenumber of load stations 410 as the number of fasteners 110 that will beassembled into the cardiac implant. Furthermore, the loading fixture 400accommodates multiple fasteners 110 having retention pins 112 that aretethered together, such as described above with reference to FIGS.21A-21D. That is, the tethers 370 are flexible, enabling the retentionpins 112 for a group of tethered fasteners to be manipulated throughadjacent lead-in cavities 430, either one at a time or simultaneously.Alternatively, the tethers 370 could be made more rigid such that aplurality of retention pins 112 can be pulled at the same time. However,the distance between the retention pins 112 determined by the length ofthe rigid tethers 370 would have to be the same as the distance betweenthe fasteners 110 on the cardiac implant as well as the distance betweenthe load stations 410 in the loading feature 400.

While the invention has been described in its preferred embodiments, itis to be understood that the words which have been used are words ofdescription and not of limitation. Therefore, changes may be made withinthe appended claims without departing from the true scope of theinvention.

What is claimed is:
 1. A cardiac implant anchoring system, comprising: acardiac implant sized to be implanted at a native heart valve annulusand arranged around a flow orifice through the cardiac implant throughwhich blood will flow axially from an inflow side to an outflow sidethereof when implanted, the cardiac implant having a pliant sealing edgearound an outer periphery defining inflow and outflow faces, the sealingedge having formed therein a plurality of generally axial slits thatopen radially outward and are each configured to laterally receivesutures extending between the inflow and outflow faces for anchoring thecardiac implant to the native heart valve annulus.
 2. The system ofclaim 1, wherein the sealing edge is ring-shaped and located around aperiphery of the inner frame, the sealing edge including a sponge memberencapsulated in a fabric cover, the fabric cover defining a series ofaxial slits and the sponge member having a series of grooves or recessesaround an outer edge thereof which coincide with the series of axialslits to combine to form the axial slits in the sealing edge.
 3. Thesystem of claim 2, further including a plurality of knotless suturefasteners positioned within the recesses in the sponge member, eachsuture fastener having an axial slot sized to receive a suture such thata suture may be passed through one of the axial slits in the sealingedge into the axial slot of the suture fastener.
 4. The system of claim2, further including a retention disc within the fabric cover and inabutment with the sponge member, the retention disc having a series ofapertures that coincide with the recesses in the sponge member and aplurality of channels providing an opening between each aperture and anouter edge of the retention disc.
 5. The system of claim 1, furtherincluding a plurality of knotless suture fasteners one of which islocated adjacent each of the axial slits in the sealing edge, eachsuture fastener defines a suture passage having an open state whichpermits a suture to slide axially therethrough and a closed state whichprevents axial movement of the suture in at least one direction, thecardiac implant capable of being anchored to a native annulus withoutthe use of knots by passing sutures pre-installed at the annulus intoeach suture fastener and converting the suture fasteners to their closedstates.
 6. The system of claim 5, wherein each suture fastener has anaxial slot sized to receive a suture such that a suture may be passedinto the axial slot of the suture fastener.
 7. The system of claim 5,wherein each suture fastener is embedded within recesses formed in thesealing edge.
 8. The system of claim 7, wherein each suture fastener hasan axial slot sized to receive a suture such that a suture may be passedinto the axial slot of the suture fastener, and wherein each suturefastener has anti-rotation structure that ensure that the axial slot onthe suture fastener remains aligned with a corresponding axial slit inthe sealing edge.
 9. The system of claim 8, wherein the anti-rotationstructure is selected from the group consisting of a flat portion on thesuture fastener that registers with a flat within a corresponding recessin the sealing edge, and a mating rib and channel formed on opposingsurfaces of the suture fastener and corresponding recess.
 10. The systemof claim 5, wherein each suture fastener is positioned outside of and inabutment with one of the inflow or outflow faces of the sealing edge.11. The system of claim 10, wherein each suture fastener is secured tothe sealing edge with sutures or adhesives.
 12. The system of claim 5,wherein each suture fastener has an outer wall defining a suturepassage-forming lumen extending from a proximal end to a distal end anda collapsible wall structure, wherein the collapsible wall structure inthe open state does not restrict relative movement between the suturefastener and a suture therein and the collapsible wall structure in theclosed state restricts movement of a suture through the suture fastenerin at least one direction, and wherein each suture fastener furtherincludes a retention member coupled thereto in the open state, theretention member having a hypotube which fits closely within the lumenof the suture fastener and maintains the collapsible wall structure inits open state, and upon removal of the retention member and hypotube,the suture fastener converts to the closed state and the collapsiblewall structure collapses inward to clamp onto a suture.
 13. The systemof claim 12, further including a tether connected to a plurality of theretention pins such that a plurality of the retention pins may beremoved in one action.
 14. The system of claim 5, wherein each suturefastener comprises: a bifurcated locking clamp including a pair ofsubstantially similar clamp halves each having an exterior surface andan inner surface facing the inner surface of the other clamp half todefine a suture passage-forming variable sized slot therebetween, theclamp halves being connected for movement toward or away from oneanother while being fixed axially with respect to one another; a biasingmember positioned on the outside of the locking clamp having a relaxedsize that, in the absence of an object in the slot, urges the innersurfaces of the clamp halves together; and a retention member positionedbetween the clamp halves against the force of the biasing member andhaving a thickness that maintains the slot width large enough to permitpassage of a suture therethrough, wherein removal of the retentionmember permits the biasing member to urge the inner surfaces of theclamp halves together and clamp the suture therebetween.
 15. The systemof claim 14, further including a tether connected to a plurality of theretention pins such that a plurality of the retention pins may beremoved in one action.
 16. The system of claim 1, wherein the cardiacimplant is a prosthetic heart valve having an inner frame arrangedaround the flow orifice and occluding members mounted to move within theinner frame that provide one-way flow through the valve.
 17. The systemof claim 16, further including a plurality of knotless suture fastenersone of which is located adjacent each of the axial slits in the sealingedge, each suture fastener defines a suture passage having an open statewhich permits a suture to slide axially therethrough and a closed statewhich prevents axial movement of the suture in at least one direction,the heart valve capable of being anchored to a native annulus withoutthe use of knots by passing sutures pre-installed at the annulus intoeach suture fastener and converting the suture fasteners to their closedstates
 18. The system of claim 17, wherein the inner frame defines threecantilevered commissure posts extending in an outflow direction andevenly distributed around the flow orifice, wherein there are threeflexible leaflets each supported by two of the commissures, and whereinthere is one axial slit and corresponding suture fastener aligned witheach of the commissure posts, and a number of axial slits andcorresponding suture fasteners evenly distributed between the commissureposts.
 19. The system of claim 18, wherein there are 12 to 18 axialslits around the sealing edge of the heart valve.
 20. The system ofclaim 1, wherein the cardiac implant is an annuloplasty ring having arigid or semi-rigid core arranged around the flow orifice.
 21. Thesystem of claim 20, wherein there are 12 to 18 axial slits around thesealing edge of the annuloplasty ring.